Off-center gate



Feb. 23, 1960 A. F. BAUER 2,925,635

OFF-CENTER GATE Filed May '7, 1957 2 Sheets-Sheet l INVENTO I Alfred F. Bauer mo figjy NEY Feb, 23, 1960 A. F. BAUER OFF-CENTER GATE 2 Sheets-Sheet 2 Filed May '7, 1957 1!!!! II If T ORNEY United States Patent OFF-CENTER GATE Alfred Ferdinand Bauer, Toledo, Ohio, assignor to National Lead Company, New York, N.Y., a corporation of New Jersey Application May 7, 1957, Serial No. 657,543

4 Claims. (Cl. 22--68) This invention relates to an improvement in pressure die casting machines. More specifically, it relates to an improvement in the shot end of large die casting ma chines.

In the production of cast pieces by pressure die casting methods, a shot of molten metal is injected under pressure into a die assembly having the desired configuration. In the cold chamber method of die casting, the molten metal is injected into the die by means of -a shot sleeve assembly which projects through the machine platen and die half terminating on the parting line face of the die and communicating with the die cavity through a system of gate runners.

Numerous dies can be used on the same die castingv machine and the dimensions of these dies vary according to the size and configurations of the article to be cast. In order to accommodate the various sized dies and properly connect them with the shot sleeve, it is customary to provide an elongated opening or slot on the vertical centerline of the front machine platen so that the sleeve location may be varied from a position at the center of the platen to a position which is below the horizontal centerline.

The distance between the front platen and the crab, on which is mounted the die closing and locking mechanism, is maintained by machine tie bars located near the corners of the platen. The closing pressure of the machine is applied on the die blocks whose height and width are usually less than those of the platen and which will normally fit on the platen within the area described by the machine bars. The application of opposing forces at unequal distances from the center result in a bending moment with the greatest force at the center of the platen. A sleeve opening through the platen at its center weakens the platen at the point where the greatest stresses are located.

In order to provide a satisfactory gating arrangement from the customary location of the shot sleeve to the cavity in large side-gated dies, it is frequently necessary to locate the die in such a position that it is not centrally located on the platen. Closing the machine with the die in an oif-center position causes unequal stresses in the machine bars and results in an unequal pressure being applied to different portions of the die assembly.

In addition to the aforementioned disadvantages of the customary center location for the shot sleeve, this location is inconvenient for the operator. As the size of die casting machines has increased to produce larger castings, it has become more diflicult for the operator to ladle metal into the pour opening in the sleeve. After each shot, the operator must reach between the opened die halves to clean the cavity area and then, when he is ready to make the next shot, he must walk around the front platen to be in a position to ladle the metal into the sleeve. In some cases, on larger machines, it is necessary for the operator to step up onto a platform in order to reach the pour opening conveniently.

It is, therefore, an object of this invention to provide "ice a pressure die casting machine in which the front platen has only one location for the shot sleeve, which will accommodate the various size dies, which location is removed from both the horizontal and vertical centerlines of the machine platen.

Another object of this invention is to provide a pressure die casting machine in which the shot sleeve opening in the machine platen is removed from the center and one which has a machine platen with no opening at its center where the greatest concentration of bending forces is located.

A further object of this invention is to provide a pressure die casting machine in which the shot sleeve is located in an off-center position so as to permit side-gated dies for large castings to be centrally located on the machine platens and to equalize the stresses in the machine tie bars.

Another object of this invention is to provide a pressure die casting machine in which the shot sleeve is located in an off-center position closer to the operators side of the machine, which position will permit satisfactory gating in the various size dies and will be more convenient for the operator ladling the molten metal into the sleeve.

These and other objects of this invention will become apparent from the following description and the drawings in which:

Figure 1 is a projected view of the shot end of a cold chamber die casting machine embodying the present invention.

Figure 2 is a view of the front platen and cover die in the direction 2-2 of Figure 1, and

Figure 3 is a face view of the front platen and shot sleeve assembly in the direction 3-3 of Figure 1.

In the drawings, cover die 30 is removably mounted on front machine platen 10 while ejector die 40 is removably mounted on sliding platen 60. Front platen 10 and sliding platen 60 are operably connected by machine bars 12 which serve as a means for aligning and guiding the sliding platen. These machine bars are rigidly but removably attached to front platen 10 and are ad-' justably attached at their other ends to the crab (not shown) to which is attached the means for opening and closing the die halves.

Shot sleeve 42 extends through front platen 10 and has reciprocably movable therein a plunger which is aflixed to one end of plunger rod 48. To the other end of plunger rod 48 is affixed a piston capable of sliding movement within shot cylinder 50 which is supported by adapter plate 52' mounted on the front platen by rods 54.

In the machine embodying the present invention, the shot sleeve 42 is located in front platen 10 at a posi' tion, indicated by reference numeral 22, which is below the horizontal centerline and to the side of the vertical centerline of the platen. The drawings show the shot sleeve in its preferred location which is equidistant from both horizontal and vertical centerlines and nearer the operators side of the machine. With the shot sleeve in this location, the holding furnace for the molten metal can be placed on the opposite side of the sleeve from the operator and it is convenient for him to ladle the metal from the furnace to the sleeve. The convenience is more obvious on larger die casting machines, because, the operator is saved many steps during a days time.

Figure 2 is a view between the die halves showing cover die 30 removably mounted on front platen 10. The end of shot sleeve 42 is shown projecting through the cover die and is connected by gate runners 38 to the die cavity 36. As may be seen from this view, with the shot sleeve in its oif-center position, side-gated dies for large castings may be positioned on the machine platen so that the center of the impression area, indicated by the reference numeral 31, is very near the center of the platen, indicated by numeral 16, and at the same time can be joined to the shot sleeve by a very satisfactory gating arrangement. By being able to center the die on the platen, stresses in the machine bars are equalized and all sides of the die are subjected to the same closing pressure.

Figure 3 is a face view of the front platen and shot cylinder 50 from the shot end of the machine showing the shot sleeve and cylinder in the preferred position which is equidistant from the horizontal and vertical centerlines of the platen. Since, due to the structure of the die casting machine and the size of the dies used therein, the force tending to cause the platen to bend is more concentrated at its center, the platen is greatly strengthened at the point of greatest strain by eliminating the customary elongated sleeve opening. With the sleeve opening in its preferred location as shown, the platen is capable of withstanding a much greater force without bending than could a similar platen having a sleeve opening near its center.

It is understood that the equipment shown for the accomplishment of the objects of this invention is susceptible to modification. Therefore, the form of the invention .described should be considered as illustrative and not limiting the scope of the following claims.

I claim:

1. A pressure die casting machine comprising a stationary platen, a movable platen, a die assembly includ ing two die halves separable in a horizontal direction mounted on said platens, said die halves enclosing a die cavity located substantially at the center of the platen, and a metal injection apparatus including a shot sleeve and plunger, the inner end of said shot sleeve extending through an opening provided therefor in said stationary platen, the outer end of said shot sleeve projecting from said platen generally normal to the mounting face of said platen, the die cavity being connected to the shot sleeve by a plurality of gate runners, said sleeve opening being located near one of the intersecting diagonal lines of the platen and a substantial distance from the center of the platen.

2. A pressure die casting machine comprising a stationary platen, a movable platen, a die assembly including two die halves separable in a horizontal direction and a metal injection apparatus including a shot sleeve and plunger, the inner endv of said shot sleeve extending through an opening provided therefor in said stationary platen, the outer end of said sleeve projecting from said platen in a direction normal to the mounting face of the platen, the die cavity being connected to the shot sleeve by a plurality of gate runners, said sleeve opening being located wholly within one of the lower quarter sections of the platen face as defined by the intersecting centerlines and having its center on the diagonal line of one of said sections a substatnial distance from the intersection of the center lines.

3. A pressure die casting machine capable of producing large castings comprising a stationary platen, a movable platen, two die halves separable in a horizontal direction mounted on said platens forming therebetween a die cavity of non-symmetrical configuration, the center of said die cavity being located near the intersection of the horizontal and vertical centerlines of the platens, and a metal injection apparatus including a shot sleeve and plunger, the inner end of said shot sleeve extending through an opening provided therefor in the stationary platen and terminating in a gate near the parting line face of the die, said gate communicating with the die cavity through a plurality of gate runners, the outer end of said sleeve projecting from the platen in a direction normal to the mounting face of the platen, said sleeve opening being located wholly within one of the lower quarter sections of the platen as defined by the intersecting centerlines of the platen near one of the diagonal lines extending from opposite corners of the platen and a substantial distance from the center of the platen.

4. A pressure die casting machine as defined in claim 3 wherein the gate and sleeve opening are each equidistant from the horizontal and vertical centerlines of the platen,

References Cited in the file of this patent UNITED STATES PATENTS 1,815,361 Morris et a1. July 21, 1931 1,927,384 Bauer Sept. 19, 1933 1,935,059 Pack Nov. 14, 1933 2,411,999 Lester Dec. 3, 1946 2,494,071 Veale Jan. 10, 1950 

